Feeding mechanism for sewing machines



Fnzme lacmmrs'u 'F011` SEWING MACHINES y Aprl 20,1926.

.1. R, MoFFjA'r-rA Fuga July 14 1921 '2 sheets-sneer?.

Patented Apr. 20, 1926.

f UNITED STATES 1,581,222 PATENT oFEicE. i

JAMES R. MOFFATT, OF CHICAGO, ILLINOIS, ASSIGNOR 'lO UNION SPECIAL MACHINE COMPANY, 0E CHICAGO, ILLINOIS, A CORPORATION 0F ILLINOIS.

FEEDING- MECHANISM FOR SEWING MACHINES.

Application filed July 14, 1921. Serial No. 484,666.

To all whom t may concern.'

Be it known that I, J AMES R. MoFFA'r'r, a citizen of the United States, residing at Chicago, `in the county of Cook, State of Illinois, have invented certain new and .useful Improvements in Feeding Mechanisms for Sewing Machines, ofwhich the following is a description, reference being hadV to the accompanying drawing and to the figures of reference markedy thereon.

V The invention relates to new and useful improvements in feeding mechanism for sewing machines and more particularly to a feeding mechanism for a sewing machine which is adapted to form a fiat covered seam.

An object of the'invention is to provide a feeding mechanism for a machine of the above type, wherein certain fabric engaging portions o-f the feed dog are capable of yield ing, so as to accommodate varying thicknesses inthe seam.

A. stillfurther object of the invention is to provide arfeeding mechanism of the above type, wherein the presser foot co-operating with the feedl dog is provided with a recess adapted to receive the extra thickness caused bythe formation of the seam, and wherein f the feed dog is provided with a yieldingly mounted `section which engages a portion of the seam passing through said recess.

These and other objects will in part be obvious and will in part be hereinafter more fully disclosed.

In the drawings which show by way kofV illustration one embodiment of the inventionl n Figure l is a plan view of a portion of a sewing machine having my improvements embodied therein; Figure 2 is a bottom plan view Lof the presser foot;

Figure 3 isfan enlarged detail sectional view through the presser foot showing the recess therein for the section of the seam;

Figure 4 is a transverse sectional view through a portion of the presser foot auf1 the feed dog;

feeding mechanism for feeding fabric sec- 'tions which are united to form a flat seam.

llie fabric sections are preferably overlapped and joined by covering stitches, said sections overlapping within the limits of the covering stitches. The covering stitched together'witli the overlapping fabric sections increases the thickness in the joined fabric sections at kthe seam. The presser foot is provided with a lrecess in rear of the openings for the needles, which recess is substantially the width ofthe covered seam and the seam after it is stitched passes into this re'- cess. The recess accommodates the rextra' thickness in the seam. The 'material is fed by a feeding mechanismr whichincludes a main feed dog having fabric engaging sections disposed at each side' of the recess in the presser foot and engaging the fabric sec-` tions at each side of the covering stitches. Said feed dog also includes yielding fabric engaging sections which are located in rear of the needles and are adapted to engage the seamedfportion of the fabric sections. Said yielding sections normally project above the outer fabric engaging sections.

Referring more in detail to the drawings,

mil

I have shown the invention as lapplied to a ymachine of the work supporting arm type.

Said work supporting arm is indicated at 1. 'Iheffabric sections being joined are fed off from the end of the arm. Said sections are held on the arm b y means of a presser foot 2.

The sections are trimmed and overlapped4 The stitching mechanism includes, as sliownin the drawings, three needles 6, 7 and 8. These needles are adapted to form needle Vthread loops a, a, a, `see Figure 7. The needle thread loops are connected on the upper face of ,the fabric sections by a cross thread c and on the lower face of the fabric sections by a looper thread b. The two fabric sections are indicated at F-F in Figure 7 and are shown as overlapped within the limits of the covering stitching mechanismthat is, the outer needle thread loops pass `through r the respective fabric sections only, while the middle needle thread loop passes through both fabric sections.

The presser foot and stitching mechanism, above referred to, are more fully shown and described in the patent granted to Joseph Berger November 5, 1918, No. 1,283,639, and a further detailed description thereo-f is not thought necessary.

The presser foot 2 in rear of the opening 9 which receives the needles is formed with a recess 10. This recess is slightly wider than the distance between the outer needles 6 and 8 and extends from the hole 9 for the needles to the rear end of the presser foot. The overlapped portions of the fabric sections, together with the covering stitches, may, therefore, pass into this recess, as clearly shown in Figure 4 of the drawings. The feeding mechanism includes a feed dog 11, which is provided with a shank 12, by which said feed dogis secured to the feedbar. Said feed dog is formed with t-wo rigid spaced fabric engaging sections 13 and 14. These fabric engaging sections 13 and 14 are connected at their outer ends by a cross bar 15, which is preferably formed integral with the fabric engaging sections 13 and 14. Extending through the cross bar 15 are two bolts 16 and 17. These bolts are threaded into a supporting plate 18, which carries fabric engaging sections 19. A sprino' 20 located in a recess in the cross bar 15 bears against the plate 18 and normally raises the fabric engaging sections 19 to a position above. the fabric engaging sections 13 and 14, as shown in Figure 6 of the drawings. The heads of the bolts 16 and 17 limit the forward movement of the fabric engaging sections 19. These fabric engaging sections 19 are disposed in rear of the needles and are so located as to move up into the recess 10. At the same time these fabric sections can yield to varying thicknesses in the seam and thus the feed dog will firmly grip the fabric sections throughout the region ofthe seam and at each side thereof, which results in a very uniform feeding of the fabric sections. An auxiliary feed dog is used in advance of the needles having a differential feeding movement.

While I have shown the invention as applied to a feed-off-the-arm machine, it will be understood that it may be equally applied to a feed-up-the-arm machine or a flat bed type of machine. The essential feature consists in the forming of the recess portion in the presser foot to receive the extra thickness of the seam and the yielding fabric engaging sections of the feed dog which engage the seamed portion for assisting in vfeeding the fabric sections. The particular feature of the yielding fabric engaging sections in the feed dog is shown, described and claimed in my co-pending application, Serial No. 484,665, liled of even date herewith and the present application is limited to the form of construction wherein the presser foot is formed with a recess and the feed dog is provided with yielding fabric engaging sections extending normally above the rigid fabric engaging sections of the feed dog.

Vhile I have described the invention as particularly useful in connection with the joining of overlapped sections, it will be understood that it may be equally useful where the fabric sections are. abutted and a plurality of cross threads or looper threads are used, thus giving considerable thickness to the seam.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. The combination of a presser foot and a feeding mechanism, said presser foot having a recess formed in the lower face thereof, and said feeding mechanism including a feed dog having rigid fabric engaging sections at each side of said recess in the presser foot, and yielding fabric engaging sections located so as to engage the fabric passing through said recess.

2. The. combination of a presser foot having an opening for the needles, a recess located in rear of said opening and extending to the rear of the presser foot, said recess being slightly wider than the distance between the outer needles, whereby overlapped stitched fabric sections may pass into said recess, and a feeding mechanism including a feed dog having rigid fabric engaging sections at each side of the recess, and yielding fabric engaging sections in rear of the needles and between said rigid sections, said yielding sections being normally projected above said rigid sections.

3. A feed dog for sewing machines comprising a supporting shank, rigid fabric engaging sections carried thereby, movable fabric engaging sections located between said rigid fabric engaging sections and at the rear ends thereof, and means for supporting said movable fabric engaging sections, whereby said sections are disposed above the fabric engaging section of said rigid sections and are capable of yielding bodily vertically so as to accommodate overlapped fabric sections passing over the feed dog and engaged thereby said movable fabric engaging sect-ions having the same longitudinal movement as the rigid fabric engaging sections.

4. A feed dog for sewing machines comprising a supporting shank, spaced rigid fabric engaging sections carried thereby, a cross bar connecting the outer ends of said rigid fabric engaging sections, bolts extending through said cross bar, a plate carried by said bolts, a spring for raising said plate, said bolts having heads for limiting the up- Ward movement of said plate, and fabric engaging sections carried by said plate.

5. A feed dog for sewing machines oomprising a supporting shank, spaced rigid fabric engaging sections carried thereby, a cross bar connecting the outer ends of said rigid fabric engaging sections, bolts extending through said crossv bar, a plate carried by said bolts, a spring for raising said plate,

said bolts having heads for limiting the up- 10 Ward movement of said plate, and fabric ,engaging sections carried by said plate, the heads of said bolts being so disposed that the fabric engaging surfaces of the movable sections are normally above the fabric en- 15 

